This invention relates generally to treadles which may be used in roadways to sense vehicular traffic flow. The invention is more particularly directed to a treadle assembly containing sealed therein a flexible circuit treadle apparatus designed to resist water and salts, to be longer lasting, easily replaceable, and difficult for vehicles to bypass.
Conventional treadle assemblies generally comprise a rubber treadle envelope containing a pair of contact strips, which are generally heavy metal plates, arranged to actuate a counter, thereby providing a record of the passage of vehicles over a predetermined section of the roadway.
Treadles have generally been utilized for counting of vehicular traffic and are conventionally disposed transversely on a roadway lane so that vehicles in that lane must pass over the treadle. Quite often treadles are placed at toll plazas which may be at a bridge, tunnel, expressway or the like.
Treadles located at such installations are subjected to extreme wear and corrosion as a result of vehicles repeatedly rolling over the same portions of the treadle, and also as a result of frequent exposure to water, salt and other environmental factors. Consequently, the treadles must be frequently replaced.
It is the general practice to replace the treadle assembly as soon as the metal contacts show signs of significant wear. As the treadle assembly is heavy and unwieldy, replacement thereof requires the efforts of several workers for a period of up to a few hours.
Conventional treadle assemblies also are stiff, and thus do not always make contact when depressed, and may be bypassed by vehicles as a result of wide spacing between the contact areas.
The present invention provides a novel treadle assembly containing a lightweight flexible circuit which is pressure sensitive, easy to replace, and difficult to bypass. The circuit is completely sealed in the treadle and is thus more resistant to water, road salt and other environmental factors than conventional treadle assemblies.